Paula, Selma and Jewel are actually optional recruits.

[Sasarai10]

Anybody else noticed that?

Well here's what happened and I came across this discovery. I forgot to put equipment on Kyril, in the battle in Small Border Village, so he got defeated before crossing the line where the first chest can be found. Since I have collected all "S" items I didn't bother to reset the battle so I continued normally. During the battle those 3 characters never appeared, so I suppose you must keep Kyril alive before reaching that certain line. So yeah they are missable characters unfortunately, and you will miss the 2 Giant Owls as well.

Also there's a special dialogue as well I've noticed. I had Kika in my party in my previous playthrough, and I triggered some different dialogue between Kika, Frederica and Paula. Although surprisingly enough Frederica wasn't in my party. So I guess you will get it only if you have Kika (maybe you must upload SIV data as well, although I'm not 100% sure).

[KFCrispy]

that's really interesting! so Kyril has to do something during that battle for the recruitments.... if I pick up from my game i'll look into some of these things.

[KFCrispy]

Ok I thought I posted about this 3 years back when I had researched the game, but I am at Small Border Village right now and confirmed: the 3 will join if Kyril completes his 3rd turn successfully. The pattern is consistent with all of the youtube videos I found.